primer design - Primer design for PCR (Sep/30/2009 )

I need to amplify the topoisomerases of trypanosoma brucei. I have acession numbers of all these and i need to design primers for them before i can do my PCR.
I have done PCR before but usually these were provided to us already so i dont know about primer design. i tried some primer design softwares already but those demand nucleotide sequence but have only the amino acid sequence from the provided acession number (eg. EAN77618_ this acession number gives a amino acid sequence of top1A of trypanosoma brucei.) Pls let me know about different primer design softwares that could be used by amino acid sequence. Also pls guide about what would be a prefect primer out of the set of primers that come as options of searh result in a primer design software.

Anyway all tools that give you the DNA sequence from the amino acid sequence, will do the job, because then you can use the DNA sequence as input in a standard primer design software such as "primer 3" or "oligo".